Nanorods of H2V3O8 wrapped in graphene sheets were prepared by hydrothermal synthesis and tested as the cathode in an aqueous rechargeable zinc-ion battery. Cyclic voltammetry indicates that H2V3O8 nanorods/graphene-523 K allows a rapid and reversible Zn2+ intercalation/extraction without the evolution of H2 and O2. The structure and composition of the composite graphene H2V3O8 nanorods [determined by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected area electron diffraction (SEAD), and X-ray photoelectron spectroscopy (XPS)] offered excellent electrochemical performance including a high specific discharge capacity of 401 mAh g–1 at 200 mA g–1, a high rate capacity of 170 mAh g–1 at 2 A g–1, and prolonged cycling stability after 200 cycles. The addition of the graphene sheets increases the diffusion coefficient of the zinc ions by an order of magnitude. Five light-emitting diodes (LEDs) are successfully powered by the aqueous rechargeable zinc-ion batteries (ARZBs) for more than 2 min to demonstrate the practical application. This work provides a creative choice for energy storage applications with low prices, green and environmental protection, and excellent safety.

Olivine LiFePO4 covered flocculent carbon layers wrapped with carbon nanotubes (CNTs) prepared by sol–gel method and calcination is used as the cathode material for aqueous rechargeable lithium-ion batteries (ARLBs).

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